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Copyright (C) 1998-99 Paul Barton-Davis
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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#include <glibmm/threads.h>
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#include "pbd/ringbuffer.h"
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/** A pool of data items that can be allocated, read from and written to
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* without system memory allocation or locking.
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Pool (std::string name, unsigned long item_size, unsigned long nitems);
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virtual void *alloc ();
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virtual void release (void *);
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std::string name() const { return _name; }
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RingBuffer<void*> free_list; ///< a list of pointers to free items within block
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void *block; ///< data storage area
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class SingleAllocMultiReleasePool : public Pool
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SingleAllocMultiReleasePool (std::string name, unsigned long item_size, unsigned long nitems);
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~SingleAllocMultiReleasePool ();
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virtual void *alloc ();
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virtual void release (void *);
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Glib::Threads::Mutex m_lock;
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class MultiAllocSingleReleasePool : public Pool
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MultiAllocSingleReleasePool (std::string name, unsigned long item_size, unsigned long nitems);
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~MultiAllocSingleReleasePool ();
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virtual void *alloc ();
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virtual void release (void *);
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Glib::Threads::Mutex m_lock;
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/** Management of a per-thread pool of data that is allocated by one thread and
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* freed by one other thread. Not safe for use when there is more than 1
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* reader and 1 writer.
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* This is basically a wrapper around a thread-local storage instance of a
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* ringbuffer, made safe for use in the case where multiple threads allocate
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* from the ringbuffer and a single thread "frees" the allocations.
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* Rather than using locks, each thread has its own ringbuffer (and associated
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* data), and so it calls alloc(), passes a pointer to the result of the alloc
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* to another thread, which later calls push() to "free" it.
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class CrossThreadPool : public Pool
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CrossThreadPool (std::string n, unsigned long isize, unsigned long nitems, PerThreadPool *);
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PerThreadPool* parent () const {
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RingBuffer<void*> pending;
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PerThreadPool* _parent;
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/** A class to manage per-thread pools of memory. One object of this class is instantiated,
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* and then it is used to create per-thread pools for 1 or more threads as required.
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const Glib::Threads::Private<CrossThreadPool>& key() const { return _key; }
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void create_per_thread_pool (std::string name, unsigned long item_size, unsigned long nitems);
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CrossThreadPool* per_thread_pool ();
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void set_trash (RingBuffer<CrossThreadPool*>* t);
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void add_to_trash (CrossThreadPool *);
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Glib::Threads::Private<CrossThreadPool> _key;
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unsigned long _item_size;
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unsigned long _nitems;
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/** mutex to protect either changes to the _trash variable, or writes to the RingBuffer */
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Glib::Threads::Mutex _trash_mutex;
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RingBuffer<CrossThreadPool*>* _trash;
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#endif // __qm_pool_h__